We consider the distributed detection of an emitter using multiple sensors deployed at deterministic locations. The signal from the emitter follows a signal attenuation model dependent on the distance between the sensor and the emitter. The sensors transmit their decisions to the fusion center through a parallel access Binary Symmetric Channel (BSC) with a cross-over probability. We seek to optimize the detection performance under a prescribed false alarm at the sensor level and at the system level. We consider the triangular topology structure and using the least favorable emitter range study the impact of the BSC on the system level detection fusion rules. The MAJORITY fusion rule is found to be optimal under certain conditions.

De nos jours, il existe de nombreuses bases de données géographiques (BDG) couvrant le même territoire. Les données géographiques sont modélisées différemment (par exemple une rivière peut être modélisée par une ligne ou bien par une surface), elles sont destinées à répondre à plusieurs applications (visualisation, analyse) et elles sont créées suivant des modes d’acquisition divers (sources, processus). Tous ces facteurs créent une indépendance entre les BDG, qui pose certains problèmes à la fois aux producteurs et aux utilisateurs. Ainsi, une solution est d’expliciter les relations entre les divers objets des bases de données, c'est-à-dire de mettre en correspondance des objets homologues représentant la même réalité. Ce processus est connu sous le nom d’appariement de données géographiques. La complexité du processus d’appariement fait que les approches existantes varient en fonction des besoins auxquels l'appariement répond, et dépendent des types de données à apparier (points, lignes ou surfaces) et du niveau de détail. Nous avons remarqué que la plupart des approches sont basées sur la géométrie et les relations topologiques des objets géographiques et très peu sont celles qui prennent en compte l’information descriptive des objets géographiques. De plus, pour la plupart des approches, les critères sont enchaînés et les connaissances sont à l’intérieur du processus. Suite à cette analyse, nous proposons une approche d’appariement de données qui est guidée par des connaissances et qui prend en compte tous les critères simultanément en exploitant à la fois la géométrie, l’information descriptive et les relations entre eux. Afin de formaliser les connaissances et de modéliser leurs imperfections (imprécision, incertitude et incomplétude), nous avons utilisé la théorie des fonctions de croyance [Shafer, 1976]. Notre approche d’appariement de données est composée de cinq étapes : après une sélection des candidats, nous initialisons les masses de croyance en analysant chaque candidat indépendamment des autres au moyen des différentes connaissances exprimées par divers critères d’appariement. Ensuite, nous fusionnons les critères d’appariement et les candidats. Enfin, une décision est prise. Nous avons testé notre approche sur des données réelles ayant des niveaux de détail différents représentant le relief (données ponctuelles) et les réseaux routiers (données linéaires) / Nowadays, there are many geographic databases, (GDB), covering the same reality. The geographical data are represented differently (for example a river can be represented by a line or a polygon), they are used in different applications (visualisation, analysis) and they are created using various modes of acquisition (sources, processes). All these factors create independence between GDB, which causes problems for both producers and users. Thus, a solution is to clarify the relationships between various database objects, i.e. to match homologous objects, which represent the same reality. This process is known as spatial data matching. Because of the complexity of the matching process, the existing approaches depend on the types of data (points, lines or polygons) and the level of detail of the GDB. We realised, that most of the approaches are based on the geometry and the topology of the geographical objects, and very few approaches take into account the descriptive information of geographical objects. Besides, for most approaches, the criteria are applied one after the other and knowledge is contained within the process. Following this analysis, we proposed a matching approach that is guided by knowledge and takes into account all criteria at the same time exploiting the geometry, descriptive information and relations between geographical objects. In order to formalise knowledge and model their imperfections (imprecision, uncertainty and incompleteness), we used the Belief Theory [Shafer, 1976]. Our approach of the data matching is composed of five steps. After a selection of candidates, the masses of beliefs are initialised by analysing each candidate separately from the others using different knowledge expressed by various matching criteria. Then, the matching criteria and candidates are fusioned. Finally, a decision is taken. Our approach has been tested on real data having different levels of detail and representing relief (data points) and road networks (linear data)

Depuis le 19ème siècle, de nombreux dispositifs de protection ont été implantés en montagne pour réduire le risque torrentiel. L'évaluation multi-échelle de leur efficacité est nécessaire pour comparer et choisir les stratégies de maintenance et de gestion de l’occupation des sols. Le chapitre I met en évidence les ambiguïtés du concept d’efficacité évalué selon plusieurs critères dans un contexte d’information imparfaite, issue de sources multiples, inégalement fiables. Pour aider l’évaluation multidimensionnelle, le problème de décision est décomposé en plusieurs sous-problèmes formulés, modélisés, traités puis intégrés. L’état de l’art du chapitre II permet de retenir les méthodes de la sûreté de fonctionnement (SdF) et d'aide à la décision (AD) basées sur le Raisonnement Évidentiel, associant les ensembles flous, les possibilités, les fonctions de croyance et la fusion d’information pour traiter chaque problème. Le chapitre III explicite le concept d'efficacité puis propose une adaptation des méthodes de la SdF à la formulation multi-échelle des problèmes. Le chapitre IV adapte les méthodes d'AD basées sur le Raisonnement Évidentiel, les améliore pour mieux représenter la connaissance disponible et évaluer la qualité d’une décision, et les associe. Le chapitre V propose une méthodologie séquentielle qui intègre ces méthodes pour évaluer les mesures de protection, de l’échelle de l’ouvrage à celle du bassin d’enjeux. Enfin, le chapitre VI discute les résultats, identifie les apports respectifs de l'intégration et des nouvelles méthodes, puis décrit les perspectives de déploiement opérationnel de la méthodologie développée. / Many torrential protective check dams have been built in French mountainous areas since the 19th century. They aim to reduce risk in torrential watersheds. Analysis of their effectiveness is needed to assess residual risk and to choose the best maintenance strategy in a context of reduced budgets. Chapter I introduces main issues due both to definition of effectiveness concept and also the several criteria and system scales that have to be assessed. Moreover, required expertise is based on imperfect information, provided by several sources with different reliability levels. To help such decisions, this thesis proposes to break down general assessment into several smaller decision-making problems. In chapter II, dependability analysis tools and Evidential Reasoning based-decision-aiding methods (ER-DAMs), using fuzzy sets and possibility theories, are chosen to help individual decisions. Chapters III to V then introduce new developments. Effectiveness concept is first defined. A multi-scale dependability analysis helps to describe each decision-making problem. ER-DAMs are then adapted to help effectiveness assessment at each system’s scale. Technical improvements are provided to these methods for a better knowledge representation and final decision. Improved methods are then associated. Finally, individual problems and associated methods are integrated in a generic methodology to help torrential protective measures’ effectiveness assessment at watershed scale. The last chapter VI focuses on discussion of integrative aspects and of ER-DAMs’ specific developments. It gives some elements to improve methods but also to help operational implementation of the generic methodology.

The present paper studied the buckling phenomena of membranes under tensile load with and without central crack.  The studies of fracture mechanics are tested within certain conditions of membranes. The tensile test has been performed with Al-foil in different crack lengths, i.e. 0 mm, 12.5 mm, 25 mm and 50 mm. The numerical analysis has been carried out by Finite Element Analysis (FEA) and comparing with the theoretical and experimental results.  In this paper, the critical buckling behavior is tested, validated and compared. Same observation of patterns in experiments and the simulation are found. The influence of scale factor for imperfection setting are tested.

O intento do trabalho é verificar se empresas com ações negociadas na Bovespa enfrentam restrição ao crédito. A análise de painel com base em dados de balanço patrimonial para o período de 2001 a 2005 revelou que, diferentemente do que se esperava, empresas de grande porte apresentam maior dependência dos fluxos de caixa para efetivar seus investimentos. Todavia, há argumentos teóricos na literatura que fundamentam esses resultados, bem como outras evidências empíricas semelhantes. / The paper focuses on evaluating whether Brazilian listed firms have faced financial constraints. Relying on data over the period 2001-2005, a panel data analysis was carried out, but the evidence raised turned out differently from the initially expected: large firms are more sensitive to cash flows to undertake their investment than smaller ones. Nonetheless, the recent literature provides theoretical rationale to deal with those findings as well as empirical evidence consistent with them.

A presente pesquisa teve como objetivo avaliar a política de desoneração da folha de pagamentos da indústria de transformação por meio de uma abordagem metodológica alternativa e complementar ao método de diferenças em diferenças, que é usualmente utilizado em tais casos. Este tema é relevante na medida em que a perda de dinamismo do setor industrial brasileiro tem feito ressurgir o debate a respeito da hipótese de desindustrialização. Ainda que a ocorrência ou não deste fenômeno não seja consensual, este cenário levou o governo a retomar o uso de políticas industriais desde 2004, sendo a desoneração da folha de pagamentos uma das medidas mais relevantes tomadas recentemente para promover a recuperação do setor industrial. A medida ambiciona reduzir os custos trabalhistas para impulsionar o emprego e a produção do setor, além de melhorar sua competitividade, e se destaca pela grande quantidade de recursos empregada: entre 2011 e 2013 a renúncia fiscal associada à pollítica foi de R$ 20 bilhões. Para avaliar esta medida, a presente pesquisa considerou a tributação sobre a mão de obra como uma fonte de imperfeição no mercado de trabalho, a qual é estimada por meio da metodologia proposta por Petrin e Sivadasan (2013). Ao considerar que a política reduz tais imperfeições, foi possível estimar seu efeito no nível de emprego da indústria por meio de extensões ao modelo proposto pelos autores. Foram utilizados microdados da Pesquisa Industrial Anual (PIA-Empresa) em nível de firma entre os anos de 1996 e 2011. A variação no emprego das indústrias beneficiadas pela medida foi de apenas 0,84%, considerando somente as indústrias inicialmente beneficiadas pela política. Os efeitos da política aumentaram com sua expansão, o que ocorreu não somente como consequência do aumento no número de indústrias beneficiadas, mas também porque a medida passou a contemplar indústrias cujas elasticidades do emprego em relação aos tributos são maiores, fazendo com que o aumento no nível de emprego passasse para 5,14%. Além disso, os resultados mostraram que a variação no nível de emprego é maior para o trabalho do tipo blue collar do que para o trabalho do tipo white collar. Isto está em acordo com a teoria econômica sobre o mercado de trabalho porque um tipo de trabalho com atribuições mais específicas e que envolve maior aquisição de conhecimentos, como é o trabalho white collar, deve ser mais afetado por outras variáveis que não os tributos. / The Brazilian government and policy makers have been concerned about the industrial performance lately, which made industrial policies recover its relevance in the political agenda since 2004. One of the most important of such policies was the payroll tax exemption to some industries, which was created to reduce labor costs, and to stimulate the Brazilian industry production, employment and competitiveness. The high coverage of this policy resulted in an important reduction in the Social Security contribution: the policy has already reduced the contribution in BRL20 billion from 2011 to 2013. Both the program expenses and the perceived need to increase Brazilian industrial competitiveness are reasons to carry out a formal empirical evaluation. However, there are many factors to control in order to identify the policy effects by the Randomized Control Trials, which makes this approach hardly suitable. The methodology to estimate market imperfections developed by Petrin e Sivadasan (2013) is helpful in this case. These estimates represent any phenomena that moves the market away from competitive equilibrium, such as mark ups, firing and hiring costs, capital adjustment costs, taxes and subsides. Therefore, the payroll tax exemption can be treated as a decrease in the gap for industrial sector labor market equilibrium, and this relationship between policy and market imperfections allows the policy effects identification. The variables used are from the Annual Industrial Research - Enterprise (\"PIA - Empresa\"), and were studied at the firm level for the period between 1996 and 2011. The results suggest that the policy increased the employment level in 0.84% considering only industries selected at the policy\'s first stage. The estimated effect on employment level increases to 5.14% considering also industries benefited by the policy after its expansions, which is related to higher elasticity of employment with respect to taxes for the industries included. Besides that, results show that most of the jobs created are blue collar jobs, which is in accordance with previous expectations since white collar jobs usually requires more skilled workers and, therefore, reacts more to other factors than taxes.

O intento do trabalho é verificar se empresas com ações negociadas na Bovespa enfrentam restrição ao crédito. A análise de painel com base em dados de balanço patrimonial para o período de 2001 a 2005 revelou que, diferentemente do que se esperava, empresas de grande porte apresentam maior dependência dos fluxos de caixa para efetivar seus investimentos. Todavia, há argumentos teóricos na literatura que fundamentam esses resultados, bem como outras evidências empíricas semelhantes. / The paper focuses on evaluating whether Brazilian listed firms have faced financial constraints. Relying on data over the period 2001-2005, a panel data analysis was carried out, but the evidence raised turned out differently from the initially expected: large firms are more sensitive to cash flows to undertake their investment than smaller ones. Nonetheless, the recent literature provides theoretical rationale to deal with those findings as well as empirical evidence consistent with them.

The aim of the project presented in this thesis is to demonstrate a modelling method for predicting the variability in the ultimate load of stiffened panel under axial compression due to manufacturing variability. Bulking is sensitive to imperfections. In the case of a post-buckled panel, manu-facturing variability produces a scatter in the ultimate load. Thus, reasonable leeway for imperfections and inherent variability must be allowed in their design. Firstly, a finite element model of a particular stiffened panel was developed, and all nonlinearities within the material, boundary condition and geometry were considered. Verification and validation were performed to examine the accuracy of the buckling behaviour prediction, especially ultimate load. Experiments on 5 identical panels in design were performed to determine the level of panel-panel variation in geometry and collapse load. A data reduction programme based on the practical geometry scanning was developed, in addi-tion to which, the procedure of importing measured imperfection into Finite Ele-ment model was introduced. To identify and apply representative imperfections to the panel model, a double Fourier series representation of the random geometric distributions is attempt-ed, and was used thereby to derive a series of shapes representing random ge-ometry scatters. With these newly generated geometric imperfections, the variation in collapse load was determined, using the validated FE analysis. And also, the probability of these predicted loads was generalized.

As the two main components of household portfolios, stocks and real estate are likely to catch people¡¦s attention. Although the number of extant studies on the interaction between the stock and real estate markets is large, the views and empirical evidence in those studies show inconsistent results. This dissertation provides an explanation for the inconsistent results: market imperfection. Employing the threshold vector error correction model to examine the interaction between Taiwan¡¦s stock and real estate markets during the period from 1973Q2 to 2009Q4, the empirical results support this explanation. When the transaction benefit from the disequilibrium between the stock and real estate markets can cover the potential cost resulting from market imperfection, the relationship between the stock and real estate markets is integrated; but when there is slight disequilibrium, the price of real estate will not converge since the arbitrage benefit cannot cover the cost of transaction. As a result, the relationship is segmented. The empirical results of the study are very robust as similar conclusions result when different proxies for housing prices are used. The interactions between the stock and the sub-region housing markets also show similar results. Finally, when macroeconomic factors are considered, the asymmetric dynamic relationship is still significant.

The main aim of this thesis is to gain insight through experiments into how the deformation characteristics of a thin ring made of a metallic material such as aluminum depend on the strain-rate. More precisely, this study investigates the buckling behavior of thin metallic rings subjected to a dynamic radial compressive loading. To do so, a total of twelve experiments were performed: three experiments for each of four load levels. The specimens used were aluminum 6061-O circular rings, having a mean radius of 15.5 mm with a radius-to-thickness ratio of 31. The external pressure acting on the specimens was created via electromagnetic induction following a rapid discharge of high voltage through a solenoid that was specially manufactured to interact with the ring specimen. This created a magnetic field that interacted with the specimen and therefore set a pressure on it. Three experiments were performed for each of the following charge levels: 2 kV, 3 kV, 4 kV and 5 kV. These experiments created maximum external pressures in the specimens that varied between 7 MPa and 38 MPa. The dynamic response of the ring specimens was recorded using a digital high-speed camera; analyses of the images revealed the initial uniform radial acceleration of the rings followed by the onset and evolution of dynamic buckling. The buckling response of the aluminum rings revealed that several different wave lengths (or buckling modes) can be observed simultaneously. These wave lengths correspond to measured mode numbers between 3 and 44, depending on the rate of change of the applied loading with the higher modes selected at higher strain-rates. Superposition of several pictures taken at different times during the experiment shows that as the ring deforms, the buckling waves stay within the same angular sector, keeping the same mode numbers they initially selected all the way during deformation. Numerical simulations were performed with the finite element program ABAQUS and validated the observation that several different buckling modes appear simultaneously in the rings and that their localizations are governed by material and geometric imperfections in the specimens. / text